1. Field of the Invention
This invention relates to a binder for binding loose leaves having perforations in a line along one edge each for the binding purpose, and more particularly to a binder for loose-leaf album, notebook, a bundle of clear-film storage pouches or the like.
2. Prior Art
Binders of the structure having a line of two-piece binder rings that are opened and closed to hold loose leaves together are roughly divided into two types. One is called an externally fitted type which simply holds a number of loose leaves with a suitable binder having binder rings. The other is called an internally fitted type which comprises a binder holding loose leaves and a hard cover whose inner side has a plurality of eyelets or tacks with which to secure the binder in place.
Typical of the externally fitted type are one using a coiled spring binder inserted spirally into a number of tiny holes formed at regular intervals along one edge of a bundle of loose leaves and one using a binder with discrete, partly open or almost complete rings.
A similar externally fitted type binder free to open or close for easy replenishment of loose leaves has been proposed as Japanese Utility Model Registration No. 3001068. That loose-leaf binder comprises a first backbone plate and a second backbone plate. The first backbone plate is composed of an insertion plate and a plurality of first binder half-rings formed at given intervals along the outer edge of the insertion plate. The second backbone plate is composed of an upper plate and a lower plate both of which form a side wall having a plurality of second binder half-rings upright at given intervals along the outer edge opposite to the outer edge of the first backbone plate and, along with the side wall, a flat groove in which the insertion plate is closely fitted.
The first and second backbone plates are made as separate members capable of being freely engaged and disengaged. The front ends of the insertion plate and of the upper and lower plates that face one another are all so shaped as to form a circular cross section when the first and second backbone plates are engaged in the closed position. The first and second backbone plates have therebetween at least one means with which they can be engaged or disengaged so as to restrict the deviation of the binder half-rings from the direction in which they are abutted at the time the backbone plates are disengaged in the closed position. In addition, guide ribs and grooves are provided across the backbone plates to bring the binder half-rings of the two plates in alignment.
Problems that the Invention is to Solve
The externally fitted type ring binders are required to provide no obstacle to the turning of loose leaves. However, even the binder of the above-mentioned utility model registration presents difficulties. The reference binder depends on the intimate fitting of the insertion plate and the flat groove of the backbone plates for its intimate closure. The closing force thus obtained is strong enough to align the binder rings and maintain the rings in the aligned state satisfactorily, but there must be allowances for forming the insertion plate and flat groove and therefore the backbone plates cannot be reduced in width beyond certain limits. To be more concrete, about 8 mm is the minimum and if the backbone plates are narrower than that they cannot be engaged firmly together and they become too flexible to fit the insertion plate insecurely into the groove. The reference binder has another problem that, when the two backbone plates are to be closed together, the user has to fit the insertion plate into the flat groove and then fit the guide rib into the guide groove. Thus the backbone plates are not readily engaged or disengaged. Further, the lack of handhold renders it difficult to disengage the backbone plates and release the two-piece binder rings open.
This invention aims at solving these problems.
Means of Solving the Problems
To achieve the aim, the present invention provides a loose-leaf binder of the externally fitted type with the following construction.
In brief, the invention resides in a loose-leaf binder comprising an elongate first backbone plate having a plurality of first binder half-rings formed at given intervals upright along the outer edge thereof, and a second backbone plate having a plurality of second binder half-rings formed at given intervals upright along the edge thereof opposite to that of the first backbone plate, said first and second backbone plates being adapted to be combined to close the first and second half-rings to form complete binder rings, said first backbone plate having a plurality of through-holes formed at given intervals in the longitudinal direction of the binder, across the length thereof, and also having a plurality of engaging recesses formed in the outer edge surface on the side of said first half-rings, said second backbone plate having a plurality of pins that fit in said through-holes and a plurality of protuberances adapted to fit in said recesses in the position where said binder half-rings are closed together. With the construction described, the backbone plates may be made narrower than 8 mm, down to about 3 mm in the extreme cases, to ensure the positive pin-through-hole combination of the two backbone plates. Not only guiding and exact abutment of the half-rings to form binder rings are made possible but also the assembling and releasing of the two backbone plates are facilitated because of limited area of frictional contact between the backbone plates. In addition, the engagement of recesses with corresponding protuberances ensures fixing of the backbone plates firm closure of the binder rings to prevent unwanted release of the loose leaves.
Desirably, the first backbone plate has in its lower part a bottom plate portion with a horizontal upper surface, and the second backbone plate has a bottom surface that comes in contact with the upper surface of the bottom plate portion. When the two backbone plates are assembled together, the bottom surface of the second backbone plate is first placed on the upper surface of the bottom plate portion to facilitate the combination of the two backbone plates.
Preferably, the first and second binder half-rings have added thickness at the bases where they are attached to the first and second backbone plates in the plane perpendicular to the longitudinal direction of the binder. This reinforces the backbone plates that are slim and accordingly reduced in strength and also reinforces the binder rings.
In another desirable aspect of the invention, either the first or second backbone plate has at its one end a hook-shaped positioning projection extending across the backbone plate, and the other backbone plate has a tip adapted to engage the positioning projection. The arrangement permits easy vertical positioning of the backbone plates at the time of assembling. Alternatively, either the first or second backbone plate has at its one end a pivot for pivotally connecting the two plates.
In a further desirable aspect, either the first or second backbone plate is cut out on the inner side of its other end where the two backbone plates face each other to provide an opening large enough to admit therein means of releasing the binder rings or combined binder half-rings. Thus, when the combined binder half-rings are to be turned open, a coil or other similar means is put into the recess formed by the cutout portion to open the opposite ends of the backbone plates and then the engaging protuberances are pulled off, in succession, from the recesses, until the two backbone plates are put away from each other and the binder half-rings are set apart.